Excessive foaming is a problem that has beset the food and drink industry for many years, and it is described at some length in NOSB TAP Review Compiled by OMRI on Glycerol Monooleate Processing (Sep. 25, 2001).
According to the “NOSB Review”, and the many documents it references, mechanical and physical means including heating, centrifuging, spraying and ultrasound have been proposed to combat foaming problems.
Chemical foam control agents have also been proposed or employed (Kouloheris, A. P., Encyclopaedia of Food Technology (1974) 427-432; Zotto, A. A., Food Additives User's Handbook (1991) 236-241; Combs, C., Encyclopaedia of Food Science and Technology (2000) 844-846). Foam control agents disclosed therein include naturally occurring fats and oils, although reference is made to their effectiveness as foam control agents as being limited, due to their poor dispersability in oil/water emulsions. Other foam control agents disclosed in such references are glycerin, lecithin, silicon dioxide, silicones and glycerol monooleate. Use of glycerol monooleate is also discussed in the “NOSB Review”.
As is well known, problems with foaming and/or spurting are particularly marked in carbonated soft drinks.
Problems with carbonated beverages may occur:                a) when a carbonated beverage undergoes manufacture, including filling, when substantial agitation is often unavoidable (US 2003/0144365 A1, EP 1504678A and “NOSB Review”;        b) when a can or bottle containing a carbonated beverage spurts or gushes on being opened, perhaps having been agitated prior to dispensing, as occurs with cans or bottles dispensed by vending machines or shaken by being carried (U.S. Pat. No. 5,378,484 U.S. Pat. No. 5,820,905);        c) when simply pouring a carbonated beverage from a bottle or can into a glass or cup (U.S. Pat. No. 5,316,779).        
Minimising foaming during filling is especially important given its bottlenecking effect during plant operations and its consequent impact on cost, time and throughput volumes: “Containment and inhibition of foam is necessary in food processing for efficient operation of production equipment” (“NOSB Review”).
EP 1 504 678A concerns the use of a chemical agent to reduce foaming in a carbonated beverage. It suggests that there is a particular foaming problem with carbonated beverages containing aspartame [APM] as a sweetener. It further states that no satisfactory solution has been devised, and that silicone-based anti-foaming agents carry a bad image with respect to safety. EP 1 504 678A proposes an emulsifier with an HLB value of 1 to 14 and, preferably, a molecular weight of 50-300, to solve the over-foaming problems which arise in carbonated beverages containing aspartame. Preferred emulsifiers are glycerine fatty acid esters, particularly glycerine monofatty acid ester and diglycerine monofatty acid ester.
U.S. Pat. No. 5,316,779 discusses specifically the problem of pouring carbonated soft drinks which form a foam head which is large, and slow to collapse. It comments that carbonated beverages containing the artificial sweetener aspartame produce the most foaming, and the most persistent foam. A solution described in U.S. Pat. No. 5,316,779 is to provide a disposable container coated on its inside (for example on the bottom and side walls of a cup) with an antifoaming agent. Suitable antifoaming agents are said to be commercially available food grade dimethyl polysiloxane antifoams, for example “Dow-Corning Antifoam 1500” and “Union Carbide SAG 710”.
U.S. Pat. No. 5,568,973 describes an anti-foaming agent deposited on a stirring or straw element to be placed in a beverage receptacle. The anti-foaming agent speeds up the pouring process and is said to be useful in high volume environments, such airliners, convenience stores, and college bars. The preferred anti-foaming agent is a food grade silicone emulsion.
U.S. Pat. No. 5,820,905 focuses on the problem of “blow-off and splash of canned drinks” and describes a polyglycerol fatty acid ester as an antifoaming agent. A dispersing agent may be employed, having an HLB of at least 5. Examples include polyglycerol fatty acid esters, sucrose fatty esters, polypropylene glycol fatty acid esters, sorbitan fatty acid esters, organic monoglycerides, polysorbates, lactic acid ester derivatives, and the like. The drinks are non-carbonated drinks, which may still suffer from such problems, due to their being packaged with a positive pressure in the headspace of the cans.
U.S. Pat. No. 5,378,484 primarily describes the problem of spurting of the contents of a can containing a low acidity non-carbonated beverage on opening. It suggests the use of a defined sub-class of sucrose fatty acid esters. Furthermore the beverage may contain a hydrophilic emulsifying agent for further increasing the dispersability of the anti-foaming agent in water at a low temperature.
JP 2-27967 (Showa 63-176296) describes preventing spurting on opening a drinks can, in particular containing a low acidity drink such as coffee, cocoa or black tea, by use of a foam control agent, which may be a glycerine fatty acid ester, a sorbitan fatty acid ester or a propylene glycol fatty acid ester.
It will be apparent that very substantial efforts have been made to counter the problems documented in the prior art, of inefficiency in filling, and undesirable effects on dispensing, such as spurting or gushing on opening a bottle or can, and excessive or persistent foaming in a glass or cup.
The commonly-observed problems of foaming when opening cans and bottles and pouring the gassed beverages suggest that the problem persists, particularly in aspartame-containing carbonated “diet” or “lite” beverages. As documented in some of the prior art documents mentioned above there is a particular difficulty in achieving foam control in aspartame-containing carbonated beverages.
A further problem associated with excessive foaming is excessive loss of carbon dioxide, and/or other gas(es), if present, during filling. This is inefficient, not least in consideration of the energy required to produce bottled gases; and it is an undesirable release of gases into the environment. It would be desirable if this problem could be eased.
A yet further problem is the loss of “fizz” of gassed beverages, when poured from a container into a drinking vessel. If excessive gas is lost from the beverage there may be a marked deterioration in its drinking quality. A related problem is that the beverage left in the container (for example a reclosable bottle) may quickly lose its drinking quality or “fizz”. A technical measure which solves or reduces this problem of drinking quality, related to foaming and/or retention of gas, could be of high value.